The invention relates to the monitoring of electrical activity within the brain of a person for purposes such as, but not limited to, biofeedback-based attention training, human performance training, gaming, and relaxation training.
The term electroencephalography (EEG) is generally employed to refer to the measurement of electrical activity produced by the brain as measured or recorded from electrodes placed on the scalp of a person. Such activity is commonly termed “brainwave” activity. (The related term electroencephalogram refers to a graphic record produced by an electroencephalograph.) The resultant electrical signals from the electrodes are correspondingly termed EEG signals or brainwave signals, and are based on the electrical activity within the brain of a person.
A system for naming points on the scalp or head where EEG electrodes are placed has been developed. Thus, the International “10-20” system is widely used to describe the location of EEG scalp electrodes for standardization. The 10-20 system is based on the surface placement of the electrode and its relationship to the underlying area of cerebral cortex. The “10” and “20” refer to the actual distances between adjacent electrodes as either 10% or 20% of the total front-back or right-left distance of the skull. Further, the letters F, T, C, P and O, which stand for Frontal, Temporal, Central, Parietal and Occipital, respectively, are used to identify the lobe over which the sensor is placed. A number is further used to identify the hemisphere location. Even numbers (2, 4, 6, 8) refer to electrode positions on the right hemisphere, and odd numbers (1, 3, 5, 7) refer to electrode positions on the left hemisphere.